Introduction to Ecology
Define ecology
The scientific study of interactions
among organisms and between
organisms and the environment.
Biosphere contains the combined
portions of the planet in which all of
life exist, including land, water and
atmosphere
Level of Organization of an
Ecosystem
Species
• Species - group
of organisms so
similar to
another that they
can breed and
produce fertile
offspring
Population
• Population – same
species and live in
same area
Community
• Communities –
different populations
that live together in a
defined area
Ecosystem
• Ecosystem – a
collection of all
organisms that live in
a particular place
together with their
nonliving
environment.
Biome
• Biome – a group of
ecosystems that have
the same climate and
similar dominant
communities.
What shapes an Ecosystem?
Biotic and Abiotic
• Biotic and Abiotic factors determine the
survival and growth of an organism and the
productivity of the ecosystem in which an
organism lives.
Biotic Factors
• Living Factors that
influence an
ecosystem
• Plant life
• Animal life
Abiotic Factors
• Physical, non-living
factors that influence
an ecosystem
• Examplestemperature,
precipitation,
humidity, wind,
nutrients, sunlight
Other factors that affect an
Ecosystem
• The area where an
organism lives is
called its habitat.
• Habitats provide
populations of wildlife
with food, water,
shelter and space.
• A niche is the full
range of physical and
biological conditions
in which an organism
lives and the way in
which the organism
uses those conditions.
It is an organisms’
occupation.
Cycles that affect Ecosystems
Water Cycle
Water Cycle Definitions
• Evaporation – process of becoming a vapor; liquid to a gas
• Condensation – state of matter from gas to liquid; reverse
of vaporization
• Precipitation – the amount of water that falls to earth as
snow, sleet, hail, rain, mist
• Transpiration – loss of water from a plant through its
leaves
• Runoff – the flow of water, from snow and rain
• Infiltration – process by which water on the ground enters
soil
Carbon Cycle
CO2 Cycle Description
• Plants release O2 into atmosphere as a
waste product
• Animals release CO2 into atmosphere as a
waste product
• Factories and cars release CO2 into
atmosphere through combustion.
• Plants use CO2 during photosynthesis and
animals use O2 for respiration.
Energy Flow
• Every organism needs energy to power
life’s processes
• The flow of energy through an ecosystem is
one of the most important factors that
determines the ability to sustain life
Autotrophs
• Captures energy from sunlight or chemicals
and use that energy to produce food.
• Other names are producers or plants.
• Are essential for the flow of energy through
the biosphere
• Produce food through Photosynthesis
Examples ofAutotrophs
Heterotrophs
• Organisms that rely on other organisms for
their energy and food supply.
• Consumer is another name
• Types of Consumers
•
•
•
•
•
Herbivores
Carnivores
Omnivores
Decomposers
Detritivores
Examples of Consumers
Decomposers
• Breaks down
dead/decay matter
• Bacteria and fungi are
examples of
decomposers
• Detritivores feed on
plant/animal remains
• Millipedes and
earthworms are
detritivores
Parasites
A parasite is an organism
that lives on or in a host
organism and gets its food
from or at the expense of
its host.
Example – Tick, Flea, Tapeworm
Energy Flow
Energy flows through an ecosystem in one direction from the
sun to autotrophs (producers) and then to heterotrophs
(consumers).
Food Chains
• A food chain is a
series of steps in
which organisms
transfer energy by
eating and being eaten.
Food Web
• A network of complex
feeding relationships
among the various
organisms in an
ecosystem
Energy Pyramid
• Trophic level is each step
in a food chain/web
• A diagram that shows the
amount of energy or
matter contained within
each trophic level in a
food chain/web
• Only about 10% of the
energy available within
one trophic level is passed
to organisms in the next
trophic level.
• Ecological Succession
a series of predictable
changes in an
environment
Succession
• Primary Succession – succession that occurs
on the surface where no soil exists
• Pioneer Species first species to populate the
area
• Examples- lichen and moss
Examples of Pioneer Species
• Lichen
Succession
• Secondary Succession – following a
disturbance that destroys a community
without destroying the soil.
• Example- land cleared and plowed for
farming
• Example – Fires set by lightning